Incandescent lamp



` Jan. 24, 1933. F. J. ALDERSON 1,895,143

INCANDESCENT LAMP Filed oct. 2a, 1927 "3m/XM1 Patented Jan. 24, 1933 UNrrfEn 'FREDERICK JACKSON ALDERSON, or KINGSTONONTARIO, CANABA, ASSIGNOROF ONE! HALF To JOHN `ivrcan'rnun PATRICK, or KINGSTON, ONTARIO, CANADA INCANnEsoENT LAMP Application filed oetoberas, 1927, serial No. 229,469, and in canada october l1,1927'.

This invention relates to improvements in incandescent lamps and' more particularly to electric incandescent lamps for use in automobile headlights and the Aobjects of the in vention are to overcome glare by eliminating direct radiation from the lament.

Further objects are to provide an improved incandescent lamp of this description that can be manufactured and placed on the market at substantially the same price as existing lamps of this description.

It is well known in the art that glare from automobile headlights is not only objectionable but absolutely dangerous and that many attempts have been made to eliminate it witln out reducing distant visibility.

In endeavoring andl experimenting to provide an incandescent lamp which practically eliminates glare the causes to which glare may be justly attributed were carefully studied and they would appear to be as fol.- lows Firstddirect radiation on the lens from the filament.

Second-a deep glow at the base of the reflector which is particularly troublesome at some distance from the light on a narrow.

road.

Third-secondary reflection from the sidey from the filament and reducing to a mini-V mum the deep glow at the reliector base and at the same time reducing the secondary reflection from the sides.

These objects are obtained by so frosting or treating the front and krear portions of a transparent glass bulb.to provide between the frosted or light diffusing sections a cirwell known construction and shape.

.cumferential space or band' of plain( ,trans-i parent glass whereby vthe reflected light rays of, the filament are so diffused as to eliminate direct` radiation and at the `same time thereflection of the glow at the reflector base and the secondary reflection from the sides.

- lReferring now to the drawing in which like characters of reference indicate correi Referring more particularly/.to the drawing in which a preferred example of myfinvention is disclosed, A indicates-theincanldescent lamp as a'wholeparticularly adaptedV for use with automobile headlightsr and 'I provided with a transparent glassbulbllof entrally arranged in the bulb isthe filament 11 with a Vfilament support and a transparent supporting stem or base for the' filament support 12 of any .suitable material and here shown as glass.

The essential tend beyond the filament 11 while the inner or rear end portion of the globe is also frosted feature of my invention coni sists in the manner in which the bulb 1() is or otherwise, in any suitable' manner, treated as at 14, both the frosted portions 13 and 14 being spaced from one another to provide a circumferential band 15 of plain transparent glass therebetween. y

I am aware that incandescent lamps have already been manufactured in which the bulb is corrugated or rippled on the portionV opposite to the base of the lamp with a view of diffusing the rearwardly Vdirected light rays of the vlament. This in practice, however, has not pro-ved satisfactory for the elimination of glare and Iphave found that by .2 Y. y Legales` vfrosting the rear portion of the bulb to provide a clear circumferential space or ring, as above described, between it and the frosted front portion that glare is eliminated.

As shown in the modied form of bulb the glass filament supporting stem l2 may also be, with advantage, frosted lto register With the frosted rear portion of the bulb. Furthermore, a frosted ring 16, .as shown in Figl ure 3, intermediate of the transparent ring l5 may also be provided.

As many changes could be made in theA above construction and many apparently Widely differentembodiments of my invention, Within vthe scope of the claim, constructed Without departing from the vspirit n or scope thereof, it is intended that allmatter contained in the Vaccoinpianying specification and drawing shall be interpreted as il-k '2O lustrativeand notin alimiting sense.

VVI-hatv I claim. as my invention is In an incandescent lampiA of the character described, the combination with a forwardA light diffusing zone surrounding 'the front fend'of the Ylamp .and extending midway thereof', a second restricted light diffusing Zone around the base of the lamp., a light diffusing band intermediate of the aforementioned light diffusing Zones and light transmitting 3-0 zones betweenthe light diffusing band .and

the front and base light diusing Zones and of substantially equal area,l of a filamentv cooperative With all the aforementioned Zones and terminating Within the forward light diffusing zone, whereby direct radiation from the filament ifs eliminated and the diffused light spread to illuminate the sides of a road and thelike. Y j f In Witness whereof I have hereunto -set my 40 hand. y

FREDERICK JACKSON ALDERSN. 

